Season 1 aired almost 8 years ago.  It was poorly recieved due to animation quality and story changes.  So it was discontinued in anime form.  While the main series Danmachi is working on its 5th season.

Sword Oratoria the stakes are higher, much darker and provides the mindset of the other major characters that are skipped in the main series.

The manga series of sword oratoria is far more along than Danmachi.  Be a lot easier to convert to anime.  The amazing world building would draw in more fans toward the books